Tuning mechanism



Filed Jan. 7, 1947 P 1949- K. L. HENDERSON 2,482,181

. TUNING MECHANISM 2 Sheets-Sheet l INVENTOR. KENNETH L. HENDERSON BYJ KM -ATTORNEY p 1949- K. 1.. HENDERSON 2,482,181

' TUNING MECHANISM 2 Sh ae'ts-Sheet 2 Filed Jan. 7, 1947 Fl G 7 INVENTOR. KENNETH HENDERSON YJKM ATTORNEY Patented Sept. 20, 1949 UNITED STA-T E S? PATEN T OF F I C E.

T NING MECHANISM este N- Y. ss sn r Kenneth L. Henderson,

to Stromberg-Garlson Company,

of New York a corporation 7 Claims.

This. invention relates to variable tunin mechanismsand more particularly to stopping means. for the prevention of'over-travel of variable tuning mechanisms.

It is an object ofmy invention toprovide new andimproved means for. stopping the rotation of the-.travelingmember on members of a variable tuning. mechanism at predetermined points. It is another object of my invention to provide new and improved. means. associated with the traveling contact member. ofa variable tuning device to enable the contact member to bestopped exactly in a predetermined .desired. position.

Thepresent inventionrelates to tuning mechanisms of a type employing rigid helically-wound inductance coils and a traveling contact member, which may include rollers. engaging the turns of the coil and which ismovable. longitudinally with respect to the coil in order to effect tuning. There is provided a simple. and positive stop mechanism for halting the traveling member at adesireclplace on the coil. The stopping mechanismmay be in-the form of an adjustable nut or nuts o x mpl In case two or more movable contact members are. employed, interlocking-controls are necessary in order to. prevent conflict in the adjustment of the, various contact members. Thus, accordi vtonnef m f. mvinven o stoppin m anism is provided such thattravel of'qne tuning device. in one. directionis. limited before one end of .the coil is, reached and] limited in the opposite direction before the. device. reaches the. other con-. tact member. The other contact member is limited' in motion in the. first mentioned direction to prevent. engagement with theifirst' tuning deviceand in theopposite direction before reaching, the. other end of thet'uning coil.

The. features. of myinvention which I believe to be novel are. set forth withparticularity in the appended claims. My invention itself both as to, its or anization. and manner of. operation togatherv with further objects and advantages thereof,,may best be understood by reference to the following description taken inv connection with the accompanying drawing in which Fig. l is a perspective. view of a tuning mechanism enie bodying the principles of. my invention,,Fi g. 2 is an exploded view of'certain parts of the tuning me han m sh in la and l u t ates the parts necessary to drive the various tuning or' contact members; Fig. 3 is a perspective view of one ofthe contactmember-s, Fig; 4; is an'end view of the-tuning member-or device shown in Fig. 3, Fig. Eris-a simplified diagram illustrating the re-- lationship between the two different types of contact membersshown in Figs. 1 and 2 Fig. 6 is a plan view of. the stoppingmechanism shown in Fig. l, and Fig. '1 depicts the gearing arrangementof the stopping mechanism.

Referring to. the drawings and particularly Fig. 1, there is shown a pair of variably tuned helically wound inductance. coils l and 2, preferably tubular in cross section. Each coil is provided with a contact member carried by, traveling tuning slugsB and 4 respectively arranged for 1on-. gitudinal movement. with respect to the coil with which it is. associated as will be explained in detail hereinafter. There is also provided a second eontact member or tuning element 5 in the nature of a probe, also. arranged for longitudinal movement with. respectto one of the coils, such as coil 2 for example.

In order to support the coils l and 2 and yet leave the space within the convolutions of the coil'free to permit unobstructed movement of the tuning devices, there is provided supporting means external to the coils. In the illustrated form of my invention the supports comprise channel-shaped members or saddles 6 suitably carried by the. member T, for example, as by means of suitable fastening members la. The inside radius of the channel is substantially the same as the cross-sectional radius of the conductor used in winding the coils. The channel is formed to have the same pitch as the coils but the inside, diameter is slightly smaller than the outside diameter of the coils so that the coil may be forced into the saddle: or supporting member and securely held. The retaining effect is enhanced if the segment of the. channel extends over a little more than 180 of are. As shown in Fig. 1', I prefer to use two saddles or supports for each coil.

The tuning slugs 3 anddfwill next be described. Particular reference is made to Figs. 3 and 4. Each tuning slug comprises a generally cylindrical member 8 carried upon a shaft assembly indicated'by the numeral 9. (see Figs. 1 and 2) which extends from front to. backof the tuning mechanism. One end of the cylinder 8 has an inwardly directed flange ll]. having apair of diametricallyopposed radial slots H. The tuning slug em-. ploys. a plurality ofrollers l2, in this case three rollers spaced approximately apart, inorder tosupport" the tuning slug or device 3 within the coil and to enable its longitudinal movement therein. The'rollers' l2 engage-the inside diameter of the-inductor or coil, following the convolutions of the coil" in such a way that they give axial and rotary movement to the slug whenever rotational movement is applied as will be explained hereinafter. The shafts |3 on which the rollers are fitted are mounted on leaf springs l4 so that the rollers are always biased outwar ly into engagement with the inside surface of the coil. This feature insures good mechanical contact by the rollers despite any small inaccuracies that may occur in the diameter of the coil. In order to balance the pressure on the leaf springs, there are provided rollers if; on the opposite ends of the shafts l3 from the rollers I2. Rollers l5 also bear against the inside of the coil whenever the tuning slug or device is inserted sufiiciently into the coil. fhe shafts and rollers are positioned axially to conform to the pitch of the coil.

In order to provide electrical contact there is provided the wiper type contact member l6 suitably carried by the tuning slug. For example, the contact member 6 may be secured to the wall of cylinder 8. In order to short circuit all con volutions of the inductor which are not active in the electrical circuit, there is provided a series of contact members i7 carried by the cylinder 8 and positioned to contact the respective turns of the coil. The contact portion |6 preferably is placed ahead of the most advanced of the rollers i2 so that contact may be made between the coil and the movable contact as close as possible to its terminal when tuned to the highest frequency.

In order to rotate th tuning slug to advance or retract the slug with respect to it associated coil, there is provided a system of shafts and gearing. Only so much of the gearing is shown as appears necessary to illustrate the operation of my tuning mechanism. In order to drive the tuning slugs 3, there is provided the tubular member |8 adapted to be inserted through the opening H3 in the end of the cylinder 8. The portion I8 is provided with splines corresponding to the slots II in the cylinder 8. In order to impart rotation to the tubular member I8 and hence to the tuning slug 3, there is provided a gear 2| of suitable dimension and shape attached to the outer end of the tubular member IB in any satisfactory manner. In order to drive the gear 2|, there is provided a driving pinion 22 suitably attached to a shaft 23 which extends through the front end of the tuning unit and terminates in suitable operatin mechanism which may include the crank 24. The shaft 23 is suitably supported as by means of supporting plates 25 and 26 located at opposite ends of the tuning unit. As will be understood from a study of Fig. l, rotation of the crank 24 causes rotation of shaft 23 and gear 22 which will result in rotation of gear 2| and tubular member i8 and tuning slug 3.

Tuning slug or member 4, in this form of our invention, is simultaneously driven by suitable gearing at the other end of the unit.

In this embodiment of my invention, inductor or coil 2 is provided with a contact member, such as the coaxially arranged probe 5 carried by the shaft assembly 9. The details of the probe are not shown. In order to transmit rotary motion to the probe and longitudinal movement thereof in respect to the coil 2, the shaft member 9 is provided at one end thereof with a threaded portion 2'. arranged to engage a suitably threaded tubular member 28 carried by the end plate 29 of the turn ing unit. It will be seen from an inspection of Fig. 2 that rotation of shaft 9 causes the shaft to enter or be retracted from the tubular portion 28 according to the direction of rotation.

In order to impart rotary motion to shaft 9, the

75 comprising the end part 55 of through shaft 33 and gear 3 will be limited by threaded portion 2! is provided with an axial opening 30 of suitable shape and there is mounted on the back plate 29 a gear 3| having an axially extending shaft member 32 having the same crosssc-ctional shape as the opening 30 extending through the back plate 29 and tubular member 28 into opening 30. In order to drive gear 3| there is provided a suitable driving gear 32 suitably mounted on a shaft 33 extending to the front of the tuning unit and terminating in suitable operating mechanism which may include a crank 34.

From the foregoing, it is seen that the wiper contact or probe 5 travels laterally and together with or independently of tuning slugs 3 and 4 in the inductors or coils following the convolutions of the coils, i. e., following the same course or path of movement as one of the slugs. Referring to coil 2, it is seen that the Wiper or probe 5 must be limited in its travel in one direction before reaching th left-hand end of the coil 2, as viewed in the drawing, and be limited in the other direction before reaching the tuning slug 4, regardless of the latters position in the inductor or coil. Similarly the tuning slug 4 must be stopped before reaching the end of the coil 2 in the righthand direction or interfering with the wiper 5 after travel in the left-hand direction. In order to accomplish these limitations, there is provided the stopping mechanism 35 best seen in Fig. 6. The stopping mechanism or unit 35 is linked to the tuning drive system through driving shaft 23 and 33. The shaft 33 i provided with a gear 36 Which meshe with an idler gear 31 suitably mounted on shaft 38 which is journaled in any satisfactory manner between end plates 39 and 39a of the stop unit 35. The idler gear 31 meshes with a longitudinally extended pinion 40 which has a tapped axial opening having threaded engagement with a suitable longitudinally extending suitably threaded support member 4| which is fixed in position as by means of fastening means 42 between end plates 39 and 39a. The pinion 40 acts as a nut on the threaded member 4| so that any rotary movement of pinion 3! transmitted 3B is transposed into longitudinal movement of pinion 40. On the threaded member 4| there are positioned two stops 43 and 44 which may be nut or which may have nuts 45 and 46, respectively, suitably secured thereto. The stops 43 and 44 may be suitably secured in position as by means of stop nuts 41 and 48, respectively. It will be seen that movement of pinion 40 to the left will be halted by engagement with the stop 43 and movement toward the right stop 44. The opposed faces of the stops may be provided with sawtooth or other desired surfaces and the associated ends of pinion 40 may have corresponding surfaces if it is desired to provide a more positive stop mechanism and an arrangement which has a minimum tendency to jam. Shaft 23 is equipped with a driving gear 49 arranged for engagement with a longitudinally extended pinion 50 suitably mounted for axial movement along a threaded member 5!. The member 5| is provided with a stop 53 at the left-hand end of the device as seen in Fig. 6. The right-hand end of pinion 40 is provided with an annular shoulder 54 which serves as a stop for the end portion 55 of the pinion 58.

It is seen from Fig. 6 that the nism associated with shaft 33 is limted in one direction by engagement with a first stop 44 and in the other direction by engagement with a second stop 43 or by engagement with a third step pinion 50 dependcontact mechamg no casinos: 6i tilt? greases acedtviee asso said means com rising a air oi parallel tarts, ciatd shaft fii wliereais thesecondcontact a member carried) by each of said sha'its and device addfitd snare 2'3 liiiiited 'in the arranged for movementtherea'lon'g, means' associne direction by the third stop" comprising 'hci'ated with each of said contact moving? means easement with the" sliultlef 54 and' in the other 5 for causing movement of the respective mem= by the fourtlis'top 53. bers, first and second step means'carr-ied by mine when, by reason (it the mechanical arrangeoi said shaits for limiting-movement of the assoment of parts, different gear ratios are effective ciate'd' member art-predetermined positions cp with respect t'othe driving shafts, compensatpo'site directions; third: stop means car-ried by ing means must be provided in the stop unit. 16 the other of said shafts for limiting at a pro lhis compensation may be achieved by using determined position themovement of theothei' different numbers of threads, i. e., thread pitch, of said members in one direction, said second per unit or length on the shafts or members 4i member and one of saidstops being arranged for and M as shown in order toeliminate extra gears engagement at a predetermined point when said or gearsoiproper ratios may be"- chosen. This second member moves in the other direction. principle is applicable to any problem where a 4. A variable tu-ni-ng mechanisrrr' comprising: a. stop or interference mechanismneed'ed'on two helical coil, first and second movable contact shafts using different speeds. means" arranged for engagement with said con, While I have shown and described aparticumeans for moving each contact means with re lai embodiment of my invention, it will be ob- 20 spect to saidc0il,- stop means for limitingthe vious to those skilled in the art that changes and movement of each contact means and for remodifications may be made without departing venting interference between said contaet means', from my invention in its broader aspects. I, said means comprising a pair of parallel threadthere o e, aim in the appe d d a m o c v r ed shafts, a member carried by each of said shafts all such changes and modifications as fall withand havin th ad d engagement t it t in the true spirit and scope of my invention. permit movement therealong, means associated What I claim is: with each of said contact moving means for caus- 1. A Variable tuning mechanism comprising a ing movement of the respective members, first helical coil, first movable contact means, first and second stop means carried by one of said and second stop means for limiting the moveshafts for limiting movement of the associated ment of said first contact means at predetermember at predetermined positions in opposite mined points in each direction, a second m0vdirections and third stop means carried by the able contact means, a t d p means arrie other of said shafts for limiting at a predeterby said first contact means to stop said ec n mined position the movement of the other of contact means in one dlrectlo f v m n 5 said members in one direction, said second memand a fourth stop m n for limiting the mov ber and one of said stops being arranged for enment of said second contact means in the other gagement, t a predetermined point when said direction whereby the movement of said first second member moves in the other direction.

contact means is limited in one direction by (211- 5. A tuning mechanism comprising a helically gagement with said first stop means and in th n wound coil and having a tuning member slug arother direction by enga with Said Second ranged for longitudinal and rotary motion with s p m s or d thirdp ans dep nd respect to said coil, said member being provided upon the position of said second contact means with a plurality of rollers having engagement and said second c n means being limited in with the inner surfaces of the convolutions of said one di ect o by d third p means and said coil, said rollers being carried by longitudiin said other direction y Said fourth Stop nally extending shafts mounted for rotation on means. i said slug, means for biasing said rollers into said 2. A variable tunm mechenlsm c mp a engagement, and means for balancing the efiect helical coil, first movable contact mean first of said biasing means comprising rollers carand seco ds p means for llmltmg the mOVeried by said shafts longitudinally spaced apart ment of said first contact means at predeterfrom the first mentioned rollers and engaging mined points in each dlrection, a second movother turns f said 1 able contact means, a third stop means carried In tuning mech'amsm a helical 0011 a fir t by Said fi Contact e s to 5130p Said Second contact bearing assembly including a. first concontact means 1n one direc ion of movement and tact member arranged for longitudinal movement a fourth stop means for limiting the movement of with respect t said 11 whereby said first said second contact means in the other direction tact member engages Said coil a Second Contact whereby the move Sa1d first Contact bearing assembly including a second contact means is llmlted In One dlrecfilon lf engagement member arranged for longitudinal movement with sa d fir Stop mean? m the other with respect to said coil whereby said second condirection by engagement Wlth 531d secPnd stop tact member engages said coil along a path of fileans )jgsald fthirdjl stop maans tdepsendm upon movement which may result in physical engage- D 1011 0 5&1 sewn f a n ment between said contact members and electrisaid second contact means being limited in said cal or mechanical i t f therebetween one direction by said third stop means and in m cans for individually imparting movement to sald other dlrectlon by Sam fourth stop means said assemblies in order to enable adjustment of n first, Second, and fourth Stop means bemg said assemblies with respect to said coil, and adiustable means for preventing engagement between said 3. A variab e tunlng meehanlsm comprlsmg a assemblies including stop mechanism operatively 11611081 0011, fiISt and second movable contact associated with each of said imparting means means arr ng for engagement With Said coil, and positioned in accordance with the positions means for moving each contact means with reof the corresponding imparting means, said stop spect to said coil, stop means for limiting the members being arranged to engage at predetermovement of each contact means and for premined positions of said contact members as said venting interference between said contact means, assemblies are moved toward each other whereby physical engagement between said assemblies or contact members is prevented.

7. In a tuning mechanism, a helical coil, a first contact bearing assembly including a first contact member arranged for longitudinal movement with respect to said coil whereby said first contact member engages said coil, a second contact bearing assembly including a second contact member arranged for longitudinal movement with respect to said coil whereby said second contact member engages said coil along a path of movement which may result in physical engagement between said contact members and electrical or mechanical interference therebetween, means for individually imparting movement to said assemblies in order to enable adjustment of said assemblies with respect to said coil, each of said imparting means including a traveling stop member arranged to move similarly to the imparting means with which it is associated, the positions of said stop members being determined by the relative positions of said assemblies, said stop members being positioned relative to each other such that said stop members engage before physical engagement between said assemblies or said contact members as either or both of said imparting means are operated to cause movement of said assemblies toward each other.

KENNETH L. HENDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

